On the left is a sample of the original scan at 2400 dpi. (Actually it has been reduced to 60% of original size to fit on the screen, but this will give you the idea.) On the right is the sample reduced by 5X. It is the best resolution for the sample at 20% of its original size. (Note: Web browsers support JPEG format but not TIFF format, since TIFF images are usually too large for Web downloading. Hence the samples shown here have been converted to JPEG at compression level 1 for viewing. The conversion from TIFF to JPEG at compression level 1 does not introduce any appreciable loss in image quality.)
Shrinking the dimensions of the image does greatly reduce its clarity when viewed at this magnification (3X). However, the full sized image is too large to fit on the screen at 1:1 magnification and at 2.7MB would take too long to download on the Web. By reducing the image by 5X, it's still sharp at 1:1, it fits on the screen, and when it's properly compressed, it doesn't take too long to download on the Web.
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Reducing File Size with High Image Quality:
The image on the left was saved with PaintShopPro5 at compression level 10. It exhibits only a slight degradation in quality around the edges of the silhouette as compared to the image on the right saved at compression level 1, but it reduces the file size by almost 4X. (Note: a sample of the image at its 'best' resolution may be seen for comparison at the top of this page.)
Microsoft Photo Editor and the Default Quality Factor:
The image on the left was saved with Microsoft Photo Editor 3.0 at the default quality factor of 50. This produces a fairly small file, only 17K, but sacrifices image quality as compared to the image on the right saved with PaintShopPro5 at compression level 1.
PaintShopPro5 Compression Level 75:
The image on the left was saved with PaintShopPro5 at compression level 75. It is highly compressed with obvious quality losses at 1X magnification. Again the image on the right is for comparison and was saved with PaintShopPro5 at compression level 1.
On the left you can see a sample made with Picture Window 2.0 at 100% quality. The horizontal pattern of pixels is an anomaly created when the JPG is made on a machine with MMX hardware. This problem has been corrected in the sample on the right made with Version 2.5.
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